Moxa Technologies EDS-726 Benefits of VLANs, VLANs and Moxa EtherDevice Switch, Managing a Vlan

EDS-726 Series User’s Manual Featured Functions

Benefits of VLANs

The main benefit of VLANs is that they provide a network segmentation system that is far more flexible than traditional networks. Using VLANs also provides you with three other benefits:

yVLANs ease the relocation of devices on networks: With traditional networks, network administrators spend much of their time dealing with moves and changes. If users move to a different subnetwork, the addresses of each host must be updated manually. With a VLAN setup, if a host on VLAN Marketing, for example, is moved to a port in another part of the network, and retains its original subnet membership, you only need to specify that the new port is on VLAN Marketing. You do not need to carry out any re-cabling.

yVLANs provide extra security: Devices within each VLAN can only communicate with other devices on the same VLAN. If a device on VLAN Marketing needs to communicate with devices on VLAN Finance, the traffic must pass through a routing device or Layer 3 switch.

yVLANs help control traffic: With traditional networks, congestion can be caused by broadcast traffic that is directed to all network devices, regardless of whether or not they need it. VLANs increase the efficiency of your network because each VLAN can be set up to contain only those devices that need to communicate with each other.

VLANs and MOXA EtherDevice Switch

Your EDS-726 provides support for VLANs using IEEE Std 802.1Q-1998. This standard allows traffic from multiple VLANs to be carried across one physical link. The IEEE Std 802.1Q-1998 standard allows each port on your EDS-726 to be placed in:

yAny one VLAN defined on the EDS-726.

ySeveral VLANs at the same time using 802.1Q tagging.

The standard requires that you define the 802.1Q VLAN ID about each VLAN on your EDS-726 before the switch can use it to forward traffic:

Managing a VLAN

A new or initialized EDS-726 contains a single VLAN—the Default VLAN. This VLAN has the following definition:

yVLAN Name—Management VLAN

y802.1Q VLAN ID—1 (if tagging is required)

All the ports are initially placed in this VLAN, and it is the only VLAN that allows you to access the management software of the EDS-726 over the network.

Communication Between VLANs

If devices connected to a VLAN need to communicate to devices on a different VLAN, a router or Layer 3 switching device with connections to both VLANs needs to be installed. Communication between VLANs can only take place if they are all connected to a routing or Layer 3 switching device.

VLANs: Tagged and Untagged Membership

Your EDS-726 supports 802.1Q VLAN tagging, a system that allows traffic for multiple VLANs to be carried on a single physical (backbone, trunk) link. When setting up VLANs you need to understand when to use untagged and tagged membership of VLANs. Simply put, if a port is on a single VLAN it can be an untagged member, but if the port needs to be a member of multiple VLANs, tagged membership must be defined.

A typical host (e.g., clients) will be untagged members of one VLAN, defined as “Access Port” in EDS-726, while inter-switch connections will be tagged members of all VLANs, defined as “Trunk Port” in EDS-726.

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